The clauses below describe the needed enhancements and specific considerations to existing interfaces in order to support SMS over a generic IP-CAN.
The C or S6c interface allows the SMS-GMSC, using MAP or a Diameter based protocol, to obtain the address of the IP-Message-GW via mechanisms described in clause 5.3
The interface(s) between the IP-SM-GW and the HLR/HSS is used for:
Supporting the registration and de-registration from the IP-SM-GW to the HLR/HSS for SMS delivery.
Forwarding of the Send Routeing Information for Short Message requests from HLR/HSS to IP-SM-GW in order to return the address where the SM should be forwarded.
Interrogating the HLR/HSS using Send Routeing Information for Short Message to retrieve the IMSI and the current MSC, SGSN, MME and/or SMSF addresses.
Informing the HLR/HSS when a memory capacity exceeded condition ceases.
Retrieving SMS related data from the HLR/HSS: subscriber data of the short message service similar to the data for the current CS/PS domain and additional service data on the service authorisation of the encapsulated short message delivery via IMS, SC address for service-level interworking from Instant Message to Short Message if the SC address is stored in the HLR/HSS.
Both a Sh interface and either a J or S6c interface can be deployed between the IP-SM-GW and the HLR/HSS. During the functional allocation the change on existing MAP functions, when used, should be minimized. The deployment of the J or S6c interface is mandatory, since it is used for forwarding the SRI for SM message.
The E/Gd/Gdd/SGd interface allows the IP-SM-GW to connect to the SMS GMSC, appearing to the SMS GMSC as an MSC, SGSN, MME or SMSF.
For interworking with SMS in MME as defined in TS 23.272
, Annex C
, an IWF may be used as described in that clause.
For interworking with an SGSN supporting the Gdd interface, an IWF may be used as described in TS 23.060
The ISC interface allows the IP-SM-GW to forward the receiving message to the SIP based UE via IMS core.